Questions on External Hard Capacity

Hello. I am a WD My Passport Ultra 1TB user. I ask just because I have something else that I am curious about. For example, an external hard drive with 1TB capacity will display 930 GB when connected to a physical computer. I want to know why it’s so different.

(P.S.1 : Of course, there is nothing wrong with using it.)
(P. S2 : I’m Korean, so I’m not good at English. So I translated the questions using the translator. If anyone can answer in Korean, I would appreciate it.)

This is due to the difference in the way Microsoft calculates file sizes versus WD (and the rest of the industry). MS calculates in Binary (0’s and 1’s) whereas we calculate using the Decimal system (1-10). Here’s some more information:

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Two different mathematical systems are used to define how much information can be stored on the hard disk drive of your computer: binary or base-2 mathematics and base-10 mathematics.

In the binary or base-2 system used by the operating system, 1 gigabyte (GB) is equal to 1,073,741,824 bytes.
In the base-10 system used by hard disk drive manufacturers, 1 gigabyte (GB) is equal to 1,000,000,000 bytes (rather than the 1,073,741,824 bytes, as listed above)

Here’s a “Real HDD Capacity Calculator”

eg. 1TB = 931.3226GB

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Thank you for the good information!